Clothing for protection against stab and bullet wounds

ABSTRACT

Protective clothing, in particular clothing which protects against injuries caused by stabbing instruments, cutting instruments, projectiles or splinters, consisting of multiple layers of flat structures. At least one side of at least one of these layers has been given a ceramic coating applied by plasma spraying. The layers preferably consist of woven fabrics made from aramide fibers. The protective clothing is especially suitable for stab protection, but a combined protection against the threat of stabbing or projectile weapons can also be achieved by this clothing while providing a good standard of wearer comfort.

BACKGROUND OF THE INVENTION

The invention relates to protective clothing, in particular to clothingwhich protects against injuries caused by stabbing instruments, cuttinginstruments, projectiles or splinters, and which consists of multiplelayers of flat structures.

Several types of clothing protecting against the effects of stabbing andcutting instruments as well as against projectiles and splinters aredescribed in the prior art. Usually this type of clothing consists ofmultiple layers, the individual layers often being made from the samematerial. The use of different materials for the individual layers ishowever also well-known.

Very often aramide-fibre woven fabrics are used in the individualprotective layers, especially for so-called antiballistic protectiveclothing (clothing which provides protection against projectiles andsplinters). one example of this is DE-A 3 426 458, in which a laminatemade from such fabrics is described for use in projectile-inhibitingclothing.

Beside this, woven fabrics and other textile flat structures made fromhigh-tenacity polyethylene fibers have been suggested for use inantiballistic protective clothing.

The use of aramide fibers for protection against cuts has also beendescribed. In EP-A 224 425 a special knit construction of aramide fiberscombined with a resin finish is discussed for this type of application.

In EP-A 519 359 flat structures consisting of wrapped yarn containingaramide fibers as the core and natural or chemical fibers in the sheathwhich can easily be dyed or printed, are suggested for the manufactureof stab-, cut-, splinter- and bullet-proof clothing.

In GB-A 2 221 976 an antiballistic helmet is described whose shell isfabricated out of a textile material embedded in a plastic matrix andcoated with a thick ceramic layer applied by means of plasma spraying.This document classified as belonging to the area of hard ballisticsdoes not offer any clues to solving the problem of gaining a combinationof protection against projectiles and stabbing in soft ballisticprotective clothing.

GB-A 1 397 955 discloses a ceramic layer applied using plasma spraying.The material coated is embedded in a plastic matrix. This fiber-plasticcomposite, which is also classified as belonging to hard ballistics,possesses an antiballistic effect. This document again offers no clue asto how to solve the problem of combining protection against projectilesand against stabbing in soft ballistic protective clothing.

The improvement of clothing providing humans with protection againstinjury is an on-going task for those concerned with developing this typeof clothing. Beside improvements to the effectiveness of the protectionprovided, a worthwhile goal is above all to improve the comfort of thewearer. Also constantly in demand are approaches mapping out a simplerand cheaper method of manufacturing this type of clothing.

An especially important demand is for antiballistic clothing, i.e.,clothing which is to provide protection against projectiles andsplinters, to be designed in such a way that this clothing also protectsagainst the effects of stabbing. This demand is voiced in particular bypolice personnel, who are exposed not only to shots from projectileweapons but also to stabbing attacks.

Clothing affording combined bullet- and stab-protection is alreadywell-known in the art. In EP-A 597 165 a panel formed out ofsuperimposed woven fabrics of high-strength fibers embedded in a matrixresin is suggested for this application. The panel is employed inprotective vests in combination with layers of traditional antiballisticwoven-fabric layers, chiefly for protecting the breast and back regions.

With this type of protective clothing, as with the already proposed useof metal panels as inserts into protective vests, it cannot beguaranteed that the wearer will have the freedom of movement necessaryin a duty situation. Beside their relatively heavy weight, the fact thatthe vest inserts lack flexibility makes them a great deal lesscomfortable to wear.

Thus the task of improving this kind of protective clothing stillremained to be done, especially as to wearer comfort.

SUMMARY OF THE INVENTION

A surprising discovery has been made, namely that it is possible toachieve a decided improvement in the effectiveness of protection withoutmaking the garment less comfortable to wear, if single layers of theprotective clothing are fabricated out of flat structures which havebeen coated with a layer of ceramic material using plasma spraying. Thepreferred flat structures suitable for use as carrier materials for thiscoating consist of aramides, preferably woven fabrics of aramide fibers.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The plasma spray coating of woven fabrics, including aramide-fibre wovenfabrics, is well-known in electrical technology applications. Suchmethods and applications are described in U.S. Pat. Nos. 4,357,387,4,713,284 and DE-U 90 12 342.

Nowhere in these patent publications is mention made of the fact thatflat structures with a plasma-sprayed ceramic coating display very goodstab-protection properties and can therefore be applied to protectiveclothing with advantage. For this reason it was surprising that suchmaterials can be employed to great advantage for stab-protectiveclothing and especially for clothing which provides both stab- andbullet-protection.

A large number of different materials can be employed as carriermaterial for plasma-sprayed ceramic coatings. If they are to be suitablefor use in protective clothing, the materials must be available in theform of flat structures. These can be sheets, films, woven fabrics,knitted articles, nonwoven fabrics or thread composites. The flatstructures consisting of fibers, such as woven, knitted or nonwovenfabrics or thread composites, are all subsumed under the collective term"textile flat structures". In the scope of this invention, woven fabricsare preferred as carrier material for the ceramic coating in themanufacture of protective clothing.

So long as textile flat structures are employed and given a ceramiccoating with a plasma spray, various fibre materials can be used intheir manufacture. The preferred types of fibre are those which alreadypossess the necessary properties for stab and antiballistic protectionwithout further treatment. Aramide or glass fibers are two suchexamples. But equally, aliphatic polyamide fibers, polyester fibers orcarbon fibers can be used as carrier materials, in the form of textileflat structures, for the ceramic coating. Out of the materials named, itis the aramides which are preferred. Aramide-fibre woven fabrics areespecially preferred.

Aramides, especially aramide fibers, are well-known in the industry.They have a number of applications in the industrial textile industry inparticular. Aramides are also known as "aromatic polyamides". One tradename given to an aramide fibre is Twaron@, for example. The termaramides is understood to mean polymers which are obtained by thepolycondensation of an aromatic acid or its chlorides with an aromaticdiamine. A well-known example is poly-p-phenyleneterephthalamide, formedfrom terephthalic acid and 1,4-phenylenediamine. In the scope of thisinvention, however, polymers which are not entirely composed of aromaticcompounds but also contain aliphatic, alicyclic or heterocycliccompounds are also referred to as aramides. In the scope of theinvention, antiballistic materials are understood to mean thosematerials which provide resistance to entry by projectiles or splintersand which significantly reduce the speed of projectiles and splinterswhen hit by them.

For the ceramic coating applied by means of plasma spraying, severaldifferent oxides are suitable, such as aluminum oxide, zirconium oxide,calcium oxide, magnesium oxide, titanium dioxide or silicon dioxide.Also suitable are aluminum silicate, calcium silicate, magnesiumsilicate, silicon carbide or zirconium carbide. The substances listedhere are not the only possibilities, but are to be understood merely asexamples.

The substances mentioned can be applied on their own or in mixtures.Tests have demonstrated that it is possible to obtain more effectiveprotection using mixtures than using single substances. For instance,the ceramic coating is preferably manufactured from a mixture ofaluminum oxide and titanium oxide. Such a mixture is easy to processwith the plasma spray apparatus and provides an attractively pricedmanufacturing alternative.

Coating a flat structure with ceramic is carried out by means of aplasma spraying technique. The process and the apparatus needed arewidely known in the industry.

Plasma spraying is a thermal spraying process. Included under thiscollective term are voltaic arc spraying, flame spraying, atmosphericplasma spraying and vacuum plasma jet spraying. For the protectiveclothing of this invention, the other methods of thermal sprayingbesides atmospheric plasma spraying can be used, particularly vacuumplasma spraying. However, atmospheric plasma spraying, henceforthreferred to as "plasma spraying", is the preferable alternative for theinvention.

Applying the ceramic coating in the plasma spray apparatus is usuallyperformed with the aid of a carrier gas. In order to improve the bondingbetween the substrate and the ceramic coating, a substance which acts asa binder is often used.

The coating thickness to be applied depends on the required level ofprotection and on the desired amount of flexibility. It should be lessthan 100 μm. Coating thicknesses of below 60 μm are preferable, whilethose of 20-40 μm are especially preferred.

The ceramic coating can be applied on one or both sides of the flatstructure. In the protective clothing of this invention, flat structureswith a protective coating applied by plasma spraying on only one sideare preferred. For one thing, this is cheaper to manufacture thanarticles coated on both sides, and for another, no great improvement inthe level of stab protection has been observed when both sides of thecarrier material have been coated. Surprisingly, it was discovered thatcoating the flat structures by plasma spraying does not reduce theirflexibility. The high level of flexibility is an important factor forprotective clothing worn on the body.

The protective clothing of this invention takes the form of protectivevests, protective suits, protective gloves, etc. In the manufacture ofhelmets, too, for instance antiballistic helmets which also containmultiple layers of protective material, flat structures with a ceramiccoating applied by plasma spraying can be used. As a further example,protective shoes can also be manufactured using flat structurescontaining a ceramic coating applied by plasma spraying. The ceramiccoating, for instance as a protection against cuts, can be applied tothe sole as well as the toe cap area of the shoes.

Even beyond the scope of protective clothing, multi-layered materials,which contain at least one flat-structure layer which has been coatedwith ceramic using plasma spraying can be utilised, among other thingsin the field of object protection. For example, plastic containers forstoring hazardous chemicals and subject to vandalism can be covered withthis type of material. This can prevent the containers being puncturedby vandalism, causing these liquids to leak out.

Vehicle protection provides a further type of implementation within thefield of object protection, where flat structures containing a ceramiccoating applied by plasma spraying can again be used.

The protective clothing which is the subject of this invention can havea protective package that consists entirely of layers which have beengiven a ceramic coating by means of plasma spraying. But the combinedimplementation of coated and uncoated protective layers is preferred.

Protective packages are understood to mean superimposed layers ofantiballistic or stab-proof flat structures, for example aramide-fibrewoven fabrics. The protective clothing of this invention is especiallysuitable for combined stab and antiballistic protection against bulletsand splinters. This kind of protective clothing provides a significantlyimproved level of protection to police personnel, who in the course ofduty are exposed not only to projectile weapons and explosive bodies butalso to stabbing attacks. Here protective layers which have been given aceramic coating using plasma spraying are used in combination withtraditional antiballistic woven fabric layers which have not been givensuch a coating.

Although the ceramic coating applied by means of plasma spraying doesnot provide any additional bullet or splinter protection, since it doesnot promote the retardation of bullets or splinters, the traumaticeffect caused by a bullet striking the protective clothing issignificantly reduced. For protective clothing which is to offer thiscombined protection through the additional use of protective layershaving a plasma-sprayed ceramic coating, it is practical to increase thenumber of protective layers without detracting from the comfort to thewearer, an effective protection against both kinds of threat istherefore achieved.

For example, a vest of this kind can be formed for combinedantiballistic and stab protection in such a way that, out of the 35protective layers in all, the 25 inner layers next to the body consistof an aramide-fibre woven fabric with a ceramic coating applied byplasma spraying, and the outer ten layers consist of an aramide-fibrewoven fabric which has not been so coated.

Protective clothing which only has to provide stab protection can alsoconsist of a combination of protective layers with and without ceramiccoating. It is recommended that in this type of protective clothing thelayers coated with ceramic material are the outer layers, those layerspositioned away from the body. But the opposite arrangement, with theceramic coated layers next to the body, provides equally good protectionagainst threats by stabbing weapons.

The number of protective-clothing protective layers containing a ceramiccoating applied by means of plasma spraying depends on the requiredlevel of protection against stab wounds. The use of more than ten layerswith ceramic coating is preferred. For use in protective clothing, 20-30protective layers with a ceramic coating applied by plasma spraying aremost preferable.

In the manufacture of a bullet-proof vest, a protective package forcombined antiballistic and stab protection which consists ofsuperimposed protective layers with and without ceramic coating issealed in a jacket of PVC sheeting. The individual layers of the packagemay be sewn together, but the package can also be placed into the PVCjacket without being bonded together. It has been shown that to achievebetter stab protection it is helpful if the individual layers are notimmobile. For this reason the layers should be glued only pointwise ifat all.

In the manufacture of a bullet-proof vest, the package which is sealedin a PVC jacket is placed in a preprocessed vest, which may consist ofdyed or printed woven cotton-polyester fabric. This woven fabric thusforms the outer material of the vest. In the interest of easy removal ofthe antiballistic package, for instance for cleaning purposes, thepackage is not entirely stitched into the cover material. Instead, anopening for removal purposes is created using a zip or strip fastener.

A vest for stab protection alone can be manufactured in a similarfashion.

Apart from protection against stab wounds, the protective clothing ofthe invention also reduces the danger of injury by cutting caused bysimilar instruments to those which inflict stab wounds.

As the following example 1 will show, with the protective clothing ofthis invention stab-proof clothing can be manufactured which achieves agood level of protection with greatly reduced weight of the protectivepackage and hence improved wearer comfort. Added to that, very effectivestab protection can be obtained for antiballistic protective clothingthrough the use of protective layers containing a ceramic coatingapplied using plasma spraying.

Thus the protective clothing of the invention represents significantprogress in the manufacture of clothing which provides securitypersonnel a good level of protection in the course of their duties.

EMBODIMENT EXAMPLES Example 1

This example illustrates the advantages of the stab-protective clothingof the invention.

A woven fabric was manufactured from aramide fibers. The fibers were inthe form of a filament yarn with a titer of 930 dtex. The plain-weavefabric had a weight of 198 g/m².

A ceramic film with a thickness of 40 μm was applied to this fabricusing plasma spraying. The ceramic material consisted of 70% aluminumoxide and 30% titanium dioxide. After being coated, the fabric weighed292 g/m².

The stab protection properties were tested against the "Swiss standard",which is equivalent to the standard drawn up by the German policeauthorities. The "Swiss standard" was published in the November 1993edition of the Swiss police technical commission's "Technical guidelinesfor lightweight protective vests". According to these guidelines, a stabtest with a stiletto is carried out. As a background, plastilina ispositioned behind the protective material. A material is sufficientlystab-proof under this test guideline if the test blade has notpenetrated the plastilina by more than 20 mm.

The ceramic coated aramide-fibre woven fabric manufactured as in thisexample fulfilled the demands posed using a layer structure of 16layers, which corresponds to a total weight of about 4.8 kg/m².

A comparative test was carried out with knitted aramide-fibre fabrics,which up to now have often been used for stab-protective clothing. Inthis test an adequate stab-protection according to the "Swiss standard"was only achieved at or above a weight of 18 kg/m².

This comparison demonstrates what an advance the material of theinvention represents especially as to wearing comfort, since as aconsequence much lighter protective clothing can be manufactured fromthe material of the invention than from the material that has beenavailable up to now.

Example 2

This example demonstrates the advantages of the protective clothing ofthe invention for combined antiballistic and stab protection.

A woven fabric was manufactured out of aramide fibers. The fibers werein the form of a filament yarn with a titer of 930 dtex. The plain-weavefabric had a weight of 202 g/m².

After manufacture, this fabric was divided. About 60% was withheld fromcoating, while the remaining 40% was coated by means of plasma spraying.

A ceramic film with a thickness of 30 μm was applied. The ceramicmaterial consisted of 60% aluminum oxide and 40% titanium dioxide. Afterspray coating, the fabric weighed 284 g/m².

The fabric thus coated was further processed into a protective vestproviding combined stab and antiballistic protection. After cut-out aprotective package was made in the following way: 35 protective layerswere superimposed in such a way that 25 layers of the ceramic coatedfabric were next to the body and 10 layers of uncoated fabric were onthe outside. The protective package thus manufactured was sealed in aPVC jacket and subjected to a bombardment test. This test was carriedout with 9 mm Para (FMJ) ammunition from a distance of 10 m at an angleof 90°. The test of antiballistic effectiveness comprises both detectingwhether the structure was penetrated and examining the changes in aplastilina mass positioned behind the material being bombarded. In thelatter case, the depth of penetration of the projectile into theplastilina mass provided an approximate measure for the energy impartedby a projectile on the human body under bombardment. Penetration depthsinto the plastilina mass of up to 44 mm are permitted by policeauthorities, depending on specification. Examining the depth ofpenetration in the plastilina mass is an aid to estimating the expectedtraumatic effect caused by a projectile hitting the protective clothing.

When the vest manufactured in the way described above was bombarded,penetration did not occur until the speed reached 460 m/sec. Accordingto the specifications of the police authorities, a protective vest mustwithstand a projectile speed of up to 420 m/sec. Below this speed, nopenetration is permitted.

The depth of penetration in the plastilina, being 17-18 mm, was wellbelow the permitted values of the police authorities.

In the test of stab-proof properties carried out in accordance with the"Swiss standard", the plastilina penetration depth of 12 mm wassignificantly below the permitted maximum values.

In comparison to this, a vest manufactured in the conventional mannerwith 28 layers of fabric manufactured as described above and not ceramiccoated was subjected to bombardment. Here, penetration first occurred ata projectile speed of 500 m/sec. The penetration depth in the plastilinawas 35-38 mm.

In the stab-protection test according to the "Swiss standard", theplastilina penetration depth significantly exceeded 100 mm. Thus thetest material did not meet the stab protection requirements.

Further trials have shown that the values specified by the "Swissstandard" are not fulfilled by protective clothing made of aramidefabric which has not been given a ceramic coating, unless more than 70layers of the fabric are employed.

The comparison provided by this trial shows that for protective clothingfor both antiballistic and stab protection, a larger number of layers ofmaterial with a plasma sprayed ceramic coating must be used, in order toguarantee with confidence that the clothing will not be penetrated, butit also shows that protective clothing can be manufactured in thismanner to guarantee sufficient protection against both types of threat.In addition, and very importantly, the traumatic effect of a projectilestriking the clothing can be significantly reduced.

What is claimed is:
 1. Protective clothing comprising multiple layers offlat structures laid on top of one another which if bonded are bonded bybeing sewn together or glued together pointwise, wherein at least oneside of at least one of the layers contains a ceramic coating applied byplasma spraying.
 2. Protective clothing in accordance with claim 1,wherein at least one of the layers is a flat structure made of aramides.3. Protective clothing in accordance with claim 1, wherein at least oneof the layers consists of aramides and contains a ceramic coatingapplied by plasma spraying.
 4. Protective clothing in accordance withclaim 1, wherein at least one of the layers consists of a woven fabricmade from aramide fibers.
 5. Protective clothing in accordance withclaim 1, wherein at least one of the layers consists of a woven fabricmade from aramide fibers and containing a ceramic coating applied byplasma spraying.
 6. Protective clothing in accordance with claim 1,wherein the ceramic coating is a combination of at least two differentceramic substances.
 7. Protective clothing in accordance with claim 1,wherein the ceramic coating has a thickness of less than 100 μm. 8.Protective clothing in accordance with claim 7, wherein the ceramiccoating has a thickness between 20-40 μm.
 9. Protective clothing inaccordance with claim 1, wherein only one side of the layers contains aceramic coating applied by plasma spraying.
 10. Protective clothing inaccordance with claim 1, wherein the protective clothing comprises atleast 10 layers containing a ceramic coating applied by plasma spraying.11. Protective clothing in accordance with claim 10, wherein theprotective clothing comprises 20-30 layers containing a ceramic coatingapplied by plasma spraying.
 12. Protective clothing in accordance withclaim 1, the protective clothing comprises both layers containing aceramic coating and layers lacking a ceramic coating.
 13. Protectiveclothing in accordance with claim 1, wherein the protective clothing isstab-protective clothing.
 14. Protective clothing in accordance withclaim 1, wherein the protective clothing provides protection againststab wounds as well as against projectiles and splinters.
 15. A methodof protecting an object against stab and projectile wounds, comprisingoutfitting the object with the protective clothing of claim
 1. 16.Protective clothing in accordance with claim 1, wherein the protectiveclothing further comprises a jacket in which the multiple layers of flatstructures are sealed.
 17. Protective clothing in accordance with claim16, wherein the jacket comprises polyvinyl chloride sheeting. 18.Protective clothing in accordance with claim 1, wherein the multiplelayers of flat structures are flexible.